STANAG 5066 is a NATO specification for running data applications over HF Radio. STANAG 5066 operates over an HF modem, and provides an interface for data applications to use and share an HF modem.

STANAG 5066 provides core services to enable applications to operate efficiently over HF radio, and specifies a protocol that enables a clean separation between applications and modem/radio level. This paper describes STANAG 5066, and shows why it is key to deploying applications over HF radio.